Film such as 35mm, 120 and 620 is frequently processed in individual lengths rather than a long continuous web as would result from splicing numerous individual lengths together. For this processing the film lengths are attached to a hanger by film holders such as shown in U.S. Pat. No. 2,803,049. The lower end of the films are weighted with a similar film holder having an additional weight attached. Long films such as 36 exposure 35mm and 620 are looped double to reduce the length and therefore the size of the processing tanks. The lengths of film are processed by sequentially dunking in appropriate chemical solutions, dried and then printed.
In the past, the drying devices have consisted of an array of infrared sources in the sides of the drying chamber, fans to pressurize filtered ambient air, and discharge ports in the side walls to direct the flow of air across the suspended film. Film drying devices of this type have several disadvantages. First, they make no effort to capture and reintroduce the heated air discharged from the chamber and thus require considerable amounts of power to perform the drying function. Second, the side discharge air introduces considerable amounts of turbulance into the drying chamber and often times cause the film to touch and, therefore, stick together thereby destroying the value of the film. Third, the side discharge of the drying air frequently causes non-uniform drying of the suspended film. Fourth, the film drying chambers of the prior art make little attempt to exclude the entry of foreign matter through the open ends of the drying chamber. Thus films frequently are damaged by dust and other airborne foreign material during the drying process.